Many children receiving dialysis continue to have poor blood pressure control even when on antihypertensive treatment, a cross-sectional study found.

Action Points

This cross-sectional database study found that hypertension remains a problem for children undergoing hemodialysis whether or not antihypertensives were being prescribed.

Note that an accompanying editorial commented that the clinical consequences of hypertension in children once on dialysis are not clear.

Many children receiving dialysis continue to have poor blood pressure control even when on antihypertensive treatment, a cross-sectional study found.

Six months after beginning dialysis, 67.9% of pediatric patients with end-stage renal disease (ESRD) had hypertension that was either uncontrolled or untreated, according to Susan M. Halbach, MD, of Seattle Children's Hospital, and colleagues.

That despite the fact that 57.8% had been given antihypertensives, they reported in the April issue of the Journal of Pediatrics.

Factors that predicted higher blood pressure included age 12 or younger, black race, glomerular disease, and beginning dialysis before 2000 (P<0.0001 for all).

The cardiovascular challenges faced by children and teens with ESRD were highlighted in an editorial accompanying the study.

"A pediatric patient on dialysis has roughly the same cardiovascular risk as an 80-year-old without ESRD," wrote Sriram S. Narsipur, MD, of the State University of New York Upstate in Syracuse.

However, patient characteristics that influence blood pressure are incompletely understood, so Halbach's group analyzed data from the North American Pediatric Renal Trials and Collaborative Studies, which is a registry that enrolls patients from 150 centers.

To adjust for the effects of age, height, and sex on blood pressure, the researchers calculated standardized z scores for their analysis, which included 3,447 patients ages 1 to 21.

A total of 65.7% were on peritoneal dialysis, with the remainder being on hemodialysis.

Between 1992 and 2008, the use of antihypertensive medications among children on dialysis rose from 52% to 67% (P<0.001).

Over that time period, there also were decreases in mean systolic blood pressure z scores, from 1.7 to 1.4, and in mean diastolic scores, from 1.3 to 1 (P<0.001 for both).

"It is encouraging to see a trend of improvement of [blood pressure] control in this population over the past two decades," the researchers observed.

On a multivariate analysis to assess factors that predicted uncontrolled blood pressure, which was defined as pressures higher than the 90th percentile whether or not antihypertensive medications were used, these characteristics were associated with increased risk:

Age younger than 6, uncontrolled diastolic, OR 1.47 (95% CI 1.15 to 1.88)

Black race, systolic, OR 1.32 (95% CI 1.11 to 1.57)

Black race, diastolic, OR 1.33 (95% CI 1.12 to 1.58)

Female sex, diastolic, OR 1.19 (95% CI 1.02 to 1.38)

Use of antihypertensives at 6 months, systolic, OR 1.94 (95% CI 1.65 to 2.27)

Use of antihypertensives at 6 months, diastolic, OR 1.95 (95% CI 1.66 to 2.29)

Glomerular involvement, systolic, OR 1.26 (95% CI 1.05 to 1.52)

Glomerular involvement, diastolic, OR 1.51 (95% CI 1.26 to 1.82)

Peritoneal dialysis was associated with a greater risk of uncontrolled diastolic pressure but a lower risk for uncontrolled systolic pressure, but these were not statistically significant.

Although no studies have examined the effects of uncontrolled hypertension with mortality in children, various potential contributors have been identified in young dialysis patients, including left ventricular hypertrophy, coronary artery calcifications, and increases in carotid artery intimal medial thickness.

"Although the exact mechanisms and pathophysiology for these findings are not known, hypertension remains a modifiable risk factor that, if treated appropriately, could have significant benefit for the long-term health of children with ESRD," Halbach and colleagues stated.

Limitations of the study include the cross-sectional design, which cannot establish causality, and unavailable data on types of medications used and timing of blood pressure measurements before or after dialysis.

Narsipur's editorial also urged caution in assuming that these findings simply imply that more aggressive hypertension control is needed for children with ESRD.

"First, the actual role of hypertension leading to major clinical consequences once a patient is on dialysis is distinctly unclear, particularly with age," he wrote.

In addition, there is no evidence-based consensus on the ideal level of blood pressure for either children or adults undergoing dialysis.

He argued in favor of 24-hour ambulatory measurements, which could provide better data that could be used for diagnosis and treatment as well as for predicting end-organ damage.

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